Advice

3. Stay Active.

Testosterone adapts to your body's needs, Yu says. If you spend most of your time lying on the couch, your brain gets the message that you don't need as much to bolster your muscles and bones.

But, he says, when you're physically active, your brain sends out the signal for more of the hormone.

If you're getting little exercise now, Miner suggests starting by:

    Walking briskly at least 10 to 20 minutes a day.
    Building strength with several sessions of weights or elastic bands each week. Work with a trainer to learn proper form so you don't injure yourself.

Don't go overboard. Extreme amounts of endurance exercise -- working out at the level of elite athletes -- can lower your testosterone.